Proteolytic activity in some freshwater animals and associated microflora in a wide pH range.

Proteolytic activity in some freshwater animals (crustacean plankton, sandhopper Amphipoda sp., larvae of chironomids Chironomus sp., oligochaetes Oligohaeta sp.

[THE ROLE OF FOOD OBJECTS AND ENTERAL MICROBIOTA PROTEASES IN NUTRITIVE AND TEMPERATURE ADAPTATIONS OF THE DIGESTIVE SYSTEM IN FISH].

The review presents data on the activity and some temperature characteristics of proteases in the potential food objects of fishes and some enteral microbiota representatives that provide induced autolysis and symbiotic digestion. It is shown that during the active feeding period the total protease activity in the prey tissues exceeds the total protease activity in the fish gastric mucosa by 5-10 times. At low temperature, the relative activity of the prey tissue lysosomal hydrolases (20-35%) and the enteral microbiota enzymes (up to 45%) may exceed that of proteases synthesized by the hepatopancreas and functioning in the consumers' intestinal mucosa (less than 10% maximal activity).

Role of peptidases of the intestinal microflora and prey in temperature adaptations of the digestive system in planktivorous and benthivorous fish.

Many fish enzymatic systems possess limited adaptations to low temperature; however, little data are available to judge whether enzymes of fish prey and intestinal microbiota can mitigate this deficiency. In this study, the activity of serine peptidases (casein-lytic, mainly trypsin and hemoglobin-lytic, mainly chymotrypsin) of intestinal mucosa, chyme and intestinal microflora in four species of planktivorous (blue bream) and benthivorous (roach, crucian carp, perch) was investigated across a wide temperature range (0-70 °C) to identify adaptations to low temperature. At 0 °C, the relative activity of peptidases of intestinal mucosa (<13%) and usually intestinal microflora (5-12.

[The effect of magnetic fields on the activity of proteinases and glycosidases in the intestine of the crucian carp Carassius carassius].

It has been demonstrated by the example of the crucian carp (Carassius carassius) that a 1-hour stay of fish in a combined magnetic field with resonance parameters for calcium ions decreases the proteolytic and amylolytic activities of their intestinal enzymes. It has been found that a 1-hour exposure to a combined magnetic field with resonance parameters for potassium ions has almost no effect on the activity of proteinases, but it decreases the amylolytic activity. It has been noted that the activity of proteases and glycosidases is lower under hypomagnetic conditions.

[The effects of geomagnetic storms on proteinase and glycosidase activities in fish intestinal mucosa].

It has been demonstrated that the glycosidase activity of cyprinoid fishes (carp and crucian carp) exposed to a geomagnetic storm for up to 20 h considerably decreases; however, the proteinase activity is weakly altered (a statistically significant decrease in the enzyme activity has been observed only in fasting fish). An in vitro study of the effects of individual half hour intervals of the geomagnetic storm that correspond to the main and recovery phases on the same enzyme activities demonstrates the opposite trend. Independently of the experimental conditions, geomagnetic storms have been shown to influence the enzyme system of fasting fish negatively.